I know people who've bought them then sent them off to jewellers to be re-set in gold settings instead. So far, I haven't heard any complaints from them.
As for what I think of lab diamonds? I prefer them over the heavy pollution that mining contributes. And because I know that ethically mined certificates can be falsified and/or bought. It's not just the mining that's harmful - a lot of diamond cutters in mining countries suffer from respiratory issues later in life after a lifetime of cutting diamonds with no safety or ethical oversight. And that's one of the lines I choose to draw personally as a consumer (also stubborn refusal to fall for DeBeers' advertising).
Lab diamonds are also chemically identical to diamonds, that's why they HAVE to be marked as lab diamonds by the labs that produce them - including lightbox; because otherwise, there's no way of telling a mined or lab diamond apart strictly on the stone and chemical properties themselves. They are NOT simulants as implied by other posters - eg. Moissanite, CZ etc.